History stats - what is wrong?

Hi all
I need some help in order to record for how long my water heater switch was on the last 24 hours.

I have made the following sensor

  - platform: history_stats
    name: water heater time on
    entity_id: switch.sonoff_100099b6de
    state: 'on'
    type: time
    end: '{{ now().replace(hour=0, minute=0, second=0) }}'
      hours: 24  # Yesterday: ends today at 00:00, lasts 24 hours

I also have the following notify.yaml

  - platform: file
    name: filenotify6
    filename: /config/water heater per day.csv
    timestamp: true

and finally this automation

- id: Water Heat daily file       
  alias: Water Heat daily file
  #initial_state: 'off'
    platform: time
    at: '23:50:00'
  condition: []

    - service: notify.filenotify6
        message: "{{ states.sensor.water_heater_time_on.state }}"

So my purpose is to record in a csv file each night the time that the switch was on.

Yesterday the switch was on for 38 minutes.
However in the csv file I got 0.00

This morning the in developers tool - states I see that the state of the sensor is 0.64
So now I am wondering what is wrong with the above setup and in the excel file I have 0.00 instead of 0.64.

I am not sure but I think the problem is with the history stats and how I set the time I need to expose.
Should I change it to

end: '{{ now().replace(hour=0, minute=0, second=0) }}'
  days: 1

I have one more question but right now about this, but this is the first I need to solve.

now I am reading again the docs
should I change it to

start: '{{ now().replace(hour=0, minute=0, second=0) }}'
end: '{{ now().replace(hour=23, minute=59, second=59) }}'

what I need is to start counting at the begging of the day 00:00:00 end ends at 23:59:59